/* ilink_client.c — 微信 ClawBot iLink 最小示例（C，依赖 libcurl）
 * 流程: 扫码登录 → 长轮询收消息 → 回声回复
 * 编译: gcc ilink_client.c -o ilink -lcurl
 *
 * 注意: 为控制依赖，JSON 用最朴素的字符串查找提取，仅适合演示。
 *       正式项目请引入 cJSON，媒体加解密见 docs/03（可用 OpenSSL AES-128-ECB）。
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/stat.h>
#include <curl/curl.h>

#define BASE_URL "https://ilinkai.weixin.qq.com"
#define STATE_FILE "bridge-state.json"

/* ---------- 响应缓冲 ---------- */
struct buf { char *data; size_t len; };

static size_t on_write(char *ptr, size_t size, size_t nmemb, void *ud) {
    struct buf *b = ud;
    size_t n = size * nmemb;
    b->data = realloc(b->data, b->len + n + 1);
    memcpy(b->data + b->len, ptr, n);
    b->len += n;
    b->data[b->len] = 0;
    return n;
}

/* ---------- 状态: bot_token / 游标（极简 key=value 行存储） ---------- */
static char g_token[512] = "", g_cursor[1024] = "";

static void load_state(void) {
    FILE *f = fopen(STATE_FILE, "r");
    if (!f) return;
    char line[2048], key[64], val[1900];
    while (fgets(line, sizeof line, f))
        if (sscanf(line, "%63[^=]=%1899[^\n]", key, val) == 2) {
            if (!strcmp(key, "bot_token")) snprintf(g_token, sizeof g_token, "%s", val);
            if (!strcmp(key, "cursor"))    snprintf(g_cursor, sizeof g_cursor, "%s", val);
        }
    fclose(f);
}

static void save_state(void) {
    FILE *f = fopen(STATE_FILE, "w");
    fprintf(f, "bot_token=%s\ncursor=%s\n", g_token, g_cursor);
    fclose(f);
    chmod(STATE_FILE, 0600);
}

/* ---------- 通用请求: 鉴权头 + 防重放 X-WECHAT-UIN ---------- */
static char *http(const char *method, const char *path, const char *json_body, long timeout) {
    CURL *c = curl_easy_init();
    struct buf b = {0};
    char url[512], uin[32], auth[600];
    snprintf(url, sizeof url, "%s%s", BASE_URL, path);

    /* X-WECHAT-UIN: base64(十进制字符串(随机uint32))，简化用伪随机 */
    snprintf(uin, sizeof uin, "%u", (unsigned)(rand() ^ (unsigned)time(NULL)));
    char uin_b64[64];
    /* 极简 base64（仅数字串，查表法） */
    const char *T = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    size_t ul = strlen(uin), o = 0;
    for (size_t i = 0; i < ul; i += 3) {
        unsigned v = uin[i] << 16 | (i+1<ul ? uin[i+1] : 0) << 8 | (i+2<ul ? uin[i+2] : 0);
        uin_b64[o++] = T[v>>18&63]; uin_b64[o++] = T[v>>12&63];
        uin_b64[o++] = i+1<ul ? T[v>>6&63] : '=';
        uin_b64[o++] = i+2<ul ? T[v&63] : '=';
    }
    uin_b64[o] = 0;

    struct curl_slist *hdrs = NULL;
    hdrs = curl_slist_append(hdrs, "Content-Type: application/json");
    hdrs = curl_slist_append(hdrs, "AuthorizationType: ilink_bot_token");
    char uin_hdr[96]; snprintf(uin_hdr, sizeof uin_hdr, "X-WECHAT-UIN: %s", uin_b64);
    hdrs = curl_slist_append(hdrs, uin_hdr);
    if (g_token[0]) {
        snprintf(auth, sizeof auth, "Authorization: Bearer %s", g_token);
        hdrs = curl_slist_append(hdrs, auth);
    }

    curl_easy_setopt(c, CURLOPT_URL, url);
    curl_easy_setopt(c, CURLOPT_HTTPHEADER, hdrs);
    curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, on_write);
    curl_easy_setopt(c, CURLOPT_WRITEDATA, &b);
    curl_easy_setopt(c, CURLOPT_TIMEOUT, timeout);
    if (!strcmp(method, "POST")) curl_easy_setopt(c, CURLOPT_POSTFIELDS, json_body);

    CURLcode rc = curl_easy_perform(c);
    curl_slist_free_all(hdrs);
    curl_easy_cleanup(c);
    if (rc != CURLE_OK) { free(b.data); return NULL; }   /* 超时/网络错误返回 NULL */
    return b.data ? b.data : strdup("");
}

/* ---------- 极简 JSON 字段提取（仅演示！正式项目用 cJSON） ---------- */
static int pick(const char *json, const char *key, char *out, size_t outsz) {
    char pat[128]; snprintf(pat, sizeof pat, "\"%s\":\"", key);
    const char *p = strstr(json, pat);
    if (!p) return 0;
    p += strlen(pat);
    const char *e = strchr(p, '"');
    if (!e || (size_t)(e - p) >= outsz) return 0;
    memcpy(out, p, e - p); out[e - p] = 0;
    return 1;
}

/* ---------- 接口1+2: 扫码登录（get_bot_qrcode / get_qrcode_status） ---------- */
static void login(void) {
    char *qr = http("GET", "/ilink/bot/get_bot_qrcode?bot_type=3", NULL, 15);
    char qrcode[256], qrurl[512];
    if (!qr || !pick(qr, "qrcode", qrcode, sizeof qrcode)) { fprintf(stderr, "获取二维码失败\n"); exit(1); }
    pick(qr, "qrcode_img_content", qrurl, sizeof qrurl);
    printf("请用微信扫码: %s\n", qrurl);
    free(qr);

    char path[320], status[32], token[512];
    snprintf(path, sizeof path, "/ilink/bot/get_qrcode_status?qrcode=%s", qrcode);
    for (int i = 0; i < 480; i++) {   /* 最多等 8 分钟 */
        char *s = http("GET", path, NULL, 15);
        if (s && pick(s, "status", status, sizeof status) && !strcmp(status, "confirmed")) {
            pick(s, "bot_token", token, sizeof token);
            snprintf(g_token, sizeof g_token, "%s", token);
            save_state();
            printf("登录成功\n");
            free(s);
            return;
        }
        free(s);
        sleep(1);
    }
    fprintf(stderr, "扫码超时\n"); exit(1);
}

/* ---------- 你的 AI 后端: 替换成自己项目的调用 ---------- */
static void ask_your_ai(const char *peer, const char *text, char *out, size_t n) {
    snprintf(out, n, "你说的是：%s", text);
}

/* ---------- 接口4: POST /ilink/bot/sendmessage ---------- */
static void send_text(const char *to, const char *text, const char *ctx_token) {
    /* 演示不处理 JSON 转义与分片，正式项目务必转义 \ " 换行 并按需分片 */
    char body[4096];
    snprintf(body, sizeof body,
        "{\"msg\":{\"to_user_id\":\"%s\",\"client_id\":\"c-%ld\","
        "\"message_type\":2,\"message_state\":2,\"context_token\":\"%s\","
        "\"item_list\":[{\"type\":1,\"text_item\":{\"text\":\"%s\"}}]}}",
        to, (long)time(NULL), ctx_token, text);
    free(http("POST", "/ilink/bot/sendmessage", body, 15));
}

/* ---------- 接口3: POST /ilink/bot/getupdates 长轮询 ---------- */
static void poll_loop(void) {
    int failures = 0;
    char body[1200];
    for (;;) {
        snprintf(body, sizeof body,
            "{\"get_updates_buf\":\"%s\",\"base_info\":{\"channel_version\":\"1.0.2\"}}",
            g_cursor);
        char *resp = http("POST", "/ilink/bot/getupdates", body, 45);
        if (!resp) {   /* 超时/网络错误 */
            failures++;
            int wait = failures <= 3 ? 2 : 30;
            fprintf(stderr, "轮询异常(%d次)，%ds 后重试\n", failures, wait);
            sleep(wait);
            continue;
        }
        if (strstr(resp, "\"errcode\":-14")) {
            fprintf(stderr, "会话过期(errcode=-14)，请删除 %s 重新扫码\n", STATE_FILE);
            free(resp); exit(2);
        }
        char buf[1024];
        if (pick(resp, "get_updates_buf", buf, sizeof buf) && buf[0]) {
            snprintf(g_cursor, sizeof g_cursor, "%s", buf);
            save_state();   /* 游标立即落盘 */
        }
        /* 演示级提取: 仅取第一条消息的文本/context_token/from_user_id */
        char peer[128], token[512], text[1500];
        if (pick(resp, "from_user_id", peer, sizeof peer) &&
            pick(resp, "context_token", token, sizeof token) &&
            pick(resp, "text", text, sizeof text) &&
            !strstr(resp, "\"message_type\":2")) {
            char reply[1700];
            ask_your_ai(peer, text, reply, sizeof reply);
            send_text(peer, reply, token);
        }
        free(resp);
        failures = 0;
    }
}

int main(void) {
    srand((unsigned)time(NULL));
    curl_global_init(CURL_GLOBAL_DEFAULT);
    load_state();
    if (!g_token[0]) login();
    poll_loop();
    curl_global_cleanup();
    return 0;
}